Lecture 2: Earth System Flashcards
What are the 4 spheres of the earth?
- Geosphere (solid earth)
- Hydrosphere (earths water)
- Biosphere (life)
- Atmosphere (earths envelope of gases)
What is an isolated system?
This means that no energy can enter or escape
What is a closed system? Give an example of a closed system.
Some energy can escape and enter
Earth is an example of a closed system, the sun is able to penetrate the atmosphere and earth is able to emit greenhouse gases
What is an open system?
All energy is able to enter and escape
How did earth originate?
How did it all begin?
It began with the Big Bang, a large explosion that sent radiation the universe flying outward, which expanded to atomic particles from e=mc^2. (conversion of energy to mass)
How were the first stars produced
By the fusion of hydrogen atoms (producing helium and releasing energy in the process)
How were planets formed
Stars began to explode, sending nebulae (clouds of gas and dust) around space, the matter then began to clump together (thanks to gravity), forming large clouds.
The sun was made from this cloud of matter, and the remaining matter spiralled around the sun, the solid particles fused together to make protoplanets.
What are the inner rocky planets
Mercury
Venus
Earth
Mars
Thin atmospheres
What are the outer gaseous planets
Jupiter
Saturn
Uranus
Neptune
Thick atmospheres
How was earths interior heated?
- Decaying of radioactive elements
- Compaction of early earth
- Meteorite impacts
In earths molten interior, what happened with the metals?
The heavy metals sank to the core (iron rich core)
(Less dense mantle)
The lighter metals rose to the crust ( even less dense crust)
What is earth’s core?
It’s a composition of iron-nickel alloy, it is very dense
What is the difference between the core and the crust? (Mantle)
The difference between earths crust and core marks a change in the chemical composition
What is earths crust?
Earths thin rocky outer shell
How many atmospheres did earth have?
2: the first one was almost entirely helium and hydrogen (lost to space)
The second was produced by the outward forces of gases from its interior (CO2 and water vapour)
How was the hydrosphere formed?
As earths interior began to cool, the water vapour that was sent outward by pressure could condense to make water…… then rivers lakes oceans, etc.
How was the biosphere created?
Fossils (stromatolites) produced bacteria that was capable of photosynthesis
In order, what was earths early internal structure? (exterior to interior)
Crust
Mantle
Core
What is earths present day internal structure? Make reference to their state as well. (exterior to interior)
Lithosphere (solid brittle) Asthenosphere (near-liquid brittle) Mesosphere (solid) Outer core (liquid) Inner core (solid)
What are the three basic plate movements?
- Divergent (away from one another)
- Convergent (toward one another)
- Transform (alongside one another)
What is unique about earth?
it is the only planet that can host complex life and it is the only planet to have water of all 3 states at its surface (solid, liquid, gas)
When was earth’s moon created?
around 50 billion years after the solar system took shape
What is the lithosphere and how is it broken up?
It is the crust and the brittle part of the mantle. It is broken up by plates that float on the asthenosphere.
What is Uniformitarianism, who formulated this concept?
“the present is key to the past” - james hutton
- this means that processes that produced earths geologic features can now be assumed to produce the same features in the past.
